This invention is related to the field of processes wherein a cracked gas stream is separated to produce dilute olefin streams to be used as feedstocks to produce olefin-based derivatives. Specifically, this invention is related to the field of processes wherein a cracked gas stream is separated to produce a dilute ethylene stream and a dilute propylene stream to be used as feedstocks for producing olefin-based derivatives. More specifically, the dilute ethylene stream is used as a feedstock to produce ethylbenzene, and the dilute propylene stream is used as a feedstock to produce cumene, acrylic acid, propylene oxide or other propylene based derivatives.
Feedstock costs in the chemical industry comprise a significant portion of the manufacturing costs. Continuous research is being conducted to lower these costs by utilizing lower cost feed sources. The alkylation of benzene and other aromatics is one area where dilute olefin streams are employed to reduce feed related manufacturing costs. For example, in the production of ethylbenzene, a raw material for the production of styrene, the off-gas from a fluidized catalytic cracking unit (FCC) can be successfully employed as a cost advantaged ethylene source. The FCC off-gas is a dilute stream containing typically less than 30 mole percent ethylene. Due to the large quantities of diluents in the FCC off-gas, such as, for example, hydrogen and methane, the alkylation section of the ethylbenzene unit requires that some of the equipment be oversized. Additionally, the hydrogen sulfide content of the FCC off-gas necessitates its removal in a gas pre-treatment section and subsequent compression before it can be routed to the alkylation reactor. The requirements of having oversized equipment and gas pretreatment followed by compression greatly increase the capital costs associated with an ethylbenzene unit utilizing FCC off-gas as its feedstock compared to a conventional ethylbenzene unit that utilizes high purity, polymer grade ethylene.
There is a need in the chemical industry to reduce feedstock costs by utilizing dilute olefin streams at olefins-based derivative units rather than polymer grade olefin feedstocks. To fulfill this need, the inventors provide this inventive process. This process reduces the amount of equipment traditionally required for the production of ethylene. An example of some of the equipment that has been eliminated is the ethylene refrigeration compressor, demethanizer, cold box system, and C2 and C3 splitters. Additionally, some equipment is smaller than with conventional crackers of comparable scale. The propylene refrigeration system is reduced in size over that of a conventional cracker. This invention also benefits the olefin-based derivative units that produce, for example, ethylbenzene, cumene, acrylic acid, and propylene oxide. One of the benefits is the pretreatment normally required for the olefins-based derivative units is not necessary in this inventive process because treatment has already been accomplished in the process to produce the dilute olefins stream. In others words, this inventive process to produce dilute olefin streams and route these stream to olefins-based derivative units has a reduced capital cost over a traditional FCC off-gas process since all pretreatment and compression is handled by the dilute olefins process.
An object of this invention is to provide a process to produce a dilute ethylene stream and a dilute propylene stream from a cracked gas stream.
Another object of this invention is to provide a process to produce the dilute ethylene stream and the dilute propylene stream from a cracked gas stream generated by the steam cracking of C2 and higher hydrocarbons.
Another object of this invention is to provide a process to produce the dilute ethylene stream and dilute propylene stream wherein these streams are utilized to produce olefin-based derivatives.
Another object of this invention is to provide a process to produce a dilute ethylene stream wherein the dilute ethylene stream is used as a feedstock to produce ethylbenzene.
Another object of this invention is to provide a process to produce a dilute ethylene stream wherein the ethylbenzene unit utilizing the dilute ethylene stream does not contain pretreatment and compression zones.
Another object of this invention is to provide a process to produce a dilute propylene stream wherein the dilute propylene stream is used as a feedstock to produce cumene, acrylic acid, propylene oxide and other propylene derivatives.
Yet another object of this invention is to produce cumene, acrylic acid, and propylene oxide and other propylene derivatives without a pretreatment unit.
In accordance with one embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream from a cracked gas stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d) or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(2) hydrogenating the C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream;
(3) separating the C3+ stream in a depropanizer zone to produce a C3 stream and a C4+ stream; and
(4) reacting the C3 stream in a methylacetylene-propadiene hydrogenation (MAPD) reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing the cracked gas stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d):
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the raw cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized, cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream; and
(5) drying the wet cracked gas stream in a drying zone to form a cracked gas stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(2) compressing the C2xe2x88x92 stream in a compression zone to form a pressurized C2xe2x88x92 stream;
(3) hydrogenating the pressurized C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream;
(4) separating the C3+ stream in a depropanizer zone to produce a C3 stream and a C4+ stream; and
(5) reacting the C3 stream in a MAPD reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) hydrogenating a portion of the acetylene in the cracked gas stream in a hydrogenation zone to produce a reduced acetylene cracked gas stream;
(2) separating the reduced acetylene cracked gas stream in a deethanizer zone to produce the dilute ethylene stream and a C3+ stream;
(3) separating the C3+ stream in the depropanizer zone to produce a C3 stream and a C4+ stream; and
(4) reacting the C3 stream in a MAPD reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting of ) the following steps in the order named:
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream;
(5) drying the wet cracked gas stream in a drying zone to form a cracked gas stream;
(6) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(7) compressing the C2xe2x88x92 stream in a second compression zone to form a pressurized C2xe2x88x92stream;
(8) hydrogenating the pressurized C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream; and
(9) separating the C3+ stream in a depropanizer zone to produce a C3 stream and a C4+ stream; and
(10) reacting the C3 stream in a MAPD reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons, and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized, cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream;
(5) drying the wet cracked gas stream in a drying zone to form a cracked gas stream;
(6) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(7) hydrogenating the C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream; and
(8) separating the C3+ stream in a depropanizer zone to produce a C3 and a C4+ stream;
(9) reacting the C3 stream in a MAPD reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the raw cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized, cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream; and
(5) drying the wet cracked gas stream in a drying zone to reduce the moisture level to form a cracked gas stream
(6) hydrogenating a portion of the acetylene in the cracked gas stream in a hydrogenation zone to produce a reduced acetylene cracked gas stream;
(7) separating the reduced acetylene cracked gas stream in a deethanizer zone to produce the dilute ethylene stream and a C3+ stream;
(8) separating the C3+ stream in the depropanizer zone to produce a C3 stream and a C4+ stream; and
(9) reacting the C3 stream in a MAPD reactor zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce the dilute propylene stream.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(2) hydrogenating the C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream;
(3) routing the C3+ stream to storage or other process unit.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(2) compressing the C2xe2x88x92 stream in a compression zone to form a pressurized C2xe2x88x92 stream;
(3) hydrogenating the pressurized C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream; and
(4) routing the C3+ stream to storage or other process unit. In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) hydrogenating a portion of the acetylene in the cracked gas stream in a hydrogenation zone to produce a reduced acetylene cracked gas stream;
(2) separating the reduced acetylene cracked gas stream in a deethanizer zone to produce the dilute ethylene stream and a C3+ stream; and
(3) routing the C3+ stream to storage or other process unit.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream;
(5) drying the wet cracked gas stream in a drying zone to produce a cracked gas stream;
(6) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(7) compressing the C2xe2x88x92 stream in a second compression zone to form a pressurized C2stream;
(8) hydrogenating the pressurized C2xe2x88x92 stream in a hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream; and
(9) routing the C3+ stream to storage or other process unit.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or consisting ofxe2x80x9d) :
(1) heating a hydrocarbon feed in a cracking zone to form a cracked gas stream; wherein the cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons, and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream;
(5) drying the wet cracked gas stream in a drying zone to produce a cracked gas stream;
(6) separating the cracked gas stream in a deethanizer zone to produce a C2xe2x88x92 stream and a C3+ stream;
(7) hydrogenating the pressurized, C2xe2x88x92 stream in the hydrogenation zone to remove a portion of the acetylene to produce the dilute ethylene stream; and
(8) routing the C3+ stream to storage or other process unit.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) heating a hydrocarbon feed in a cracking zone to form a raw cracked gas stream; wherein the raw cracked gas stream comprises hydrogen, methane, C2 hydrocarbons, C3 hydrocarbons, and heavier constituents;
(2) quenching the raw cracked gas stream in a quenching zone to produce a quenched, cracked gas stream;
(3) compressing the quenched, cracked gas stream in a first compression zone to form a pressurized cracked gas stream;
(4) deacidifying the pressurized, cracked gas stream in a deacidifying zone to remove a portion of the hydrogen sulfide to form a wet cracked gas stream; and
(5) drying the cracked gas stream in a drying zone to produce a cracked gas stream.
(6) hydrogenating a portion of the acetylene in the cracked gas stream in a hydrogenation zone to produce a reduced acetylene cracked gas stream;
(7) separating the reduced acetylene cracked gas stream in a deethanizer zone to produce the dilute ethylene stream and a C3+ stream;
(8) routing the C3+ stream to storage or other process unit.
In accordance with another embodiment of this invention, a process for producing a dilute ethylene stream and a dilute propylene stream is provided, the process comprising (or optionally, xe2x80x9cconsisting essentially ofxe2x80x9d or xe2x80x9cconsisting ofxe2x80x9d) the following steps in the order named:
(1) Separating a cracked gas stream in a depropanizer zone to form a C3xe2x88x92 stream and a C4+ stream
(2) Separating the C3xe2x88x92 stream in a deethanizer zone to form a C2xe2x88x92 stream and a C3 stream.
(3) hydrogenating a portion of the acetylene in the C2xe2x88x92 stream in a hydrogenation zone to produce a dilute ethylene stream; and
(4) reacting the C3 stream in a MAPD zone to convert a portion of methylacetylene and propadiene to propylene and propane to produce said dilute propylene stream.
These objects, and other objects, will become more apparent to others with ordinary skill in the art after reading this disclosure.